Safety device.



No. 704,398 Patented July 8, I902.

A. SUNDH.

SAFETY DEVICE.

' (Application filed Oct. 12 ,1901.) (No Model.)

UNITED STATES PATENTI OFFICE.

AUGUST SUNDH, OF YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, OF EAST ORANGE, NEYV JERSEY, A CORPORATION OF NETV JERSEY.

SAFETY DEVECE.

SPECIFICATION formingpart of Letters Patent No. 704,398, dated July 8, 1902.

Application filed October 12,1901. Serial No. 78,490, (No model.)

T at whom it pray concern:

Beit known that I, AUGUST SUNDH, a citizen of the United States, residing at Yonkers, in the county of WVestchester and State of New York, have invented certain new and useful Improvements in Safety Devices, of which the following is a specification.

My invention relates to the automatic operation of switches and controlling devices [0 for dynamo-electric machines, but more particularly to the operation of electric motors.

The object of my invention is to provide an apparatus by which the operation of an electric motor is automatically controlled and r 5 quickly brought to a stop if the armature-circuit is broken or deenergized or if the fieldcircuit is broken or deenergized. In the running of ordinary motors the most obvious advantage of an arrangement such as this is to prevent the armature from being burned out when the shunt field is out of order. An apparatus such as this is particularly applicable to elevator-service where the motor is sometimes driven by the weight of the car or an overbalanced counterweight. In such cases when the shunt field breaks there is nothing to prevent the car racing, and this has been the cause of many serious accidents.

,My invention therefore consists, primarily,

0 of a safety device comprising means in the circuit of the shunt field of a motor controlling the armaturecircuit and means controlled by the armature-circuit for bringing the motor to a stop when the armature-cir- 5 cuit is broken or deenergized or when the field-circuit is broken or deenergized.

My invention is more fully illustrated in the accompanying drawing and specification, wherein the details of construction and connections are set forth, and my invention further consists in the specific arrangement of circuits and connections and apparatus for carrying out the objects hereinbefore referred to.

The drawing is a diagrammatic representation of circuits and connections embodying apparatus for carrying out my invention.

Referring to the drawing, A represents the armature of any suitable motor, and B the source of supply.

0 represents the armature-circuit or mains,

supplying current to the armature A from the source B, and D represents any suitable form of starting-switch and starting-resistance placed in the armature-circuit.

Preferably a shunt-wound motor is shown, in which E is the shunt field-winding and F the circuit of the shunt field, connected at any suitable points, as f f, to the armaturecircuit O. A controlling-switch G is shown in the armature-circuit, which may be of any suitable character, the contacts 8 s of which are controlled by a suitable electroresponsive device S, shown in this instance as an electromagnet. This electroresponsive device S is arranged in the circuit of the shunt fieldwinding, as shown, and is adapted to be energized when the field is energized. The terminals of the circuit of the field ff are preferably connected to the armature-circuit or mains O at points between the source of supplyB and the startingswitch D and control ling-switch Gr, and current is supplied to the mains 0 through suitable switches H II.

In order that the rotation of the motor may be more readily controlled and the motor brought to a stop quickly when desired in case of an emergency or otherwise, as in elevator-service, a suitable brake I is arranged to cooperate with a sheave J, connected to the motor-armature, and this brake I is controlled by an electroresponsive device K, (shown as an electro1nagnet,) energized from the armature-circuit or main circuit. Preferably this electroresponsive device K is connected to the mains O O at points between the starting and controlling switches and the armature, so that when the controlling-switch G is opened the device K will be deenergized and the brake applied. The contacts .9 s of the controlling-switch G are arranged to be opened by any suitable means, as a lever L, connected to contact 8 and a retractingspring M.

By the arrangement of circuits and apparatus shown it will be seen that it is not possible by throwing in the starting-switch to send any current through the armature A of the motorunless the field is intact and is first energized. If the field is intact, the device S will be energized, switch G closed when the switch D is closed, and the motorwill operate,

the brake I being withdrawn from the sheave J; but if for any reason the field should become deenergized, as by an injury occurring to the circuit of the same, breaking the circuit, the electroresponsive device S would become deenergized and contacts 3 s separated, thus breaking the main circuit, whereby the motor would be stopped and the brake I immediately applied.

Without limiting myself to the precise details of construction shown and described, I claim- 1. The combination of a motor, and a brakemagnet connected in a shunt to the armaturecircuit and controlled by the fieldcircuit, substantially as described.

2. The combination of a motor, a field-circuit normally closed in shunt to the mains, and a switch in the armature-circuit controlled by an electroresponsive device in said field-circuit, substantially as described.

3. The combination of a motor, a field-circuit normally closed in shunt to the mains,

- and a normally open switch in the armaturecircuit controlled by an electroresponsive device in said field-circuit, substantially as described.

4. The combination of a motor, a field-circuit normally closed in shunt to the mains, a switch in the armaturercircuit, and means controlled by the said field-circuit for closing and opening said switch, substantially as set forth.

5. The combination of a motor, its armature-circuit and shunt field winding, and means in the circuit of the shunt field controlling the armature-circuit, and a brake controlled by the armature-circuit, substantially as described.

6. Thecombination of a main circuit and a motor, its shunt field-winding, and an electroresponsive device therein controlling con tacts in the main circuit, a main circuit switch and an electroresponsive device energized from the main circuit and controlling a brake, substantially as described.

7. The combination of a main circuit and a motor, its shunt field-winding and an electroresponsive device therein controlling the operation of a switch in the main circuit, another switch in the main circuit for starting the motor, and an electroresponsive brakecontrolling device connected to the main circuit in such manner as to become deenergized when the circuit of the field-winding becomes denergizedsubstantially as described.

vogses S. The combination of a main circuit and a motor, its shunt field-winding and an electroresponsive device therein controlling the operation of a switch in the main circuit, another switch in the main circuit for starting the motor, and an electroresponsive brakecontrolling device connected in shunt with the main circuit in such manner as to become deenergized when the main circuit is broken, substantially as described.

9. The combination of a main circuit and a motor, its shunt field-winding and an electroresponsive device therein controlling the operation of a switch in the main circuit, another switch in the main circuit for starting the motor, and an electroresponsive brakecontrolling device adapted to be deenergized when the circuit of the shunt field-winding is broken, substantially as described.

10. The combination of a main circuit and a motor, its shunt field-winding and an electroresponsive device therein controlling the operation of a switch in the main circuit, a brake, and an electroresponsive brake-controlling device adapted to apply the brake when the field-winding becomes deenergized, substantially as described.

11. The combination of a source of supply and a main circuit, an armature connected thereto, starting and controlling switches in the main circuit, a shunt field-circuit connected to the main circuit at points between the source of supply and said starting and controlling switches,and an electroresponsive device in said field-circuit controlling said cont1-olling-switch,substantially as described.

12. The combination of a source of supply and a main circuit, an armature connected thereto, starting and controlling switches in the main circuit, a shunt field-circuit connected to the main circuit at points between the source of supply and said starting and controlling switches, an electroresponsive d evice in said field-circuit controlling said controlling switch, and an electroresponsive brake-controlling device connected to points on the main circuit between the starting and controlling switches and the armature, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

AUGUST SUNDII. lVitnesses:

W. L. IIASTEDT, II. R. MAnsDEN. 

